I have a ford f-150 the power steering is working fine but the pump is screaming

I've seen the reservoir get clogged and restrict fluid flow!.... Can't recall the setup on this vehicle but it's something to look in to! Might need a good flushing... Also, a new fluid type is aval. now, think it's Mercron V...maybe google that for more info... Another thing to check for is a TSB... (Technical Service Bulletin) issued to assist in correcting this problem!... Juan's random thoughts but also check for an idler/tensioner pulley bearing whine!!!